West Africa: The 2015 Season
WEST AFRICA SEASONAL ANALYSIS - 2015
HIGHLIGHTS
• The West Africa growing season of 2015 is developing under an evolving El Nino event that will peak in late
2015. Historically, this region shows significant linkages between El Nino events and seasonal rainfall deficits
particularly in the more marginal areas.
• The first stages of the season were marked by rainfall deficits across the entire region that have led to delays
in the start of the growing season and poor conditions for early crop development.
• Worst affected areas extend from northern Cote d’Ivoire, northern Ghana, Burkina Faso and across into
northern Nigeria. South-eastern Niger, central Senegal and western Mali are also facing difficult conditions.
• While there is still time to recover, well distributed July and August rainfall is now essential to improve
current prospects. Recent good rainfall in western areas of the region (Senegal, Mali) has improved
conditions but elsewhere the situation remains difficult.
• Seasonal forecasts are moderately unfavourable with indications of below average rainfall during July to
September for Senegal-Mali and Niger-Chad regions. Agrhymet Centre also issued predictions of shorter than
average growing season for the Sahelian region.
Current Status and near Future Perspectives
WEST AFRICA SEASONAL ANALYSIS - 2015
Seasonal rainfall performance
The early stages of the growing season in West Africa
have been dominated by significant rainfall deficits
across most of the region.
Until late June, central areas of Senegal, southern
Mauritania and western Mali had received less than half
of the usual rainfall – these are areas that were already
affected by a very severe drought in 2014. However,
wetter than average conditions in early July improved
this situation.
A similar situation developed in eastern Niger, northern
Nigeria and Chad—regions also affected by a poor
growing season in 2014. There has been no reprieve in
the first half of July which has further deepened
seasonal rainfall deficits. Rainfall has also been irregular
and poorly distributed across northern Cote d’Ivoire,
northern Ghana and Togo-Benin.
This situation can however still change, rapidly and
substantially, since most of the seasonal rainfall occurs
during July to September.
Seasonal cumulative rainfall until early July 2015, as a percentage of the 20-year average.
Hashed pattern indicates main agricultural areas.
Brown shades indicate below-average rainfall; blue shades indicate above-average seasonal rainfall.
WEST AFRICA SEASONAL ANALYSIS - 2015
Left: Date of onset of the growing season compared to average. Pinks and yellows to reds for delayed growing seasons, green shades for earlier than average growing seasons.
Right: early July 2015 Vegetation Index as a percentage of the 12-year average. Hashed pattern indicates main agricultural areas.
Orange shades for below-average vegetation; green shades for above-average vegetation
Onset of Season and Vegetation Status
The rainfall deficits extending across the Sahel have led to generalized delays in the onset of the growing season. Most delays are of 10-20 days, occasionally reaching up to
30 days. This is also reflected in sharply below average vegetation across the whole Sahelian zone. Consequently, there are delays in the start of the agricultural activities, as
well as replanting and stressed early crop development where the season had started on time.
Planting in the more marginal areas occurs in July. Therefore, a recovery is still possible—in fact, conditions in the wider Senegal-Mali region should now improve in
response to favourable rainfall in the first half of July. Still, no such improvements are yet expected for the wider Niger-Chad-northern Nigeria region. The situation is likely
to further worsen for the most vulnerable populations if the July rainfalls are below average.
WEST AFRICA SEASONAL ANALYSIS - 2015
The El Nino Event of 2015-2016
An El Nino event is officially active since March 2015. After remaining at relatively weak levels until
May 2015, it is now intensifying and should peak in the last quarter of 2015.
Historically, El Nino events have a significant impact on the Sahel region leading to growing season
rainfall deficits and poor vegetation development.
The early stages of the growing season have been unfavourable and conforming to the historical
patterns: the dominant features are below average rainfall, delayed onset of the planting season
and depressed vegetation levels, as the monsoon-like northward movement of the rains has been
slower than usual.
Probability of an El Nino event (red bars) vs neutral conditions (green) and La Nina
(blue). El Nino probabilities remain above 90% throughout the Sahelian growing season.
Current forecasts for July-September
July to September is the crucial period of the Sahelian rainfall season. Most forecasts predict
moderately drier than average conditions in the Senegal and Mauritania region. Similar conditions
are also forecast for the Niger-Chad areas.
The Agrhymet Centre has recently released forecasts for shorter than average growing seasons
across the Sahel.
Possibility of a region wide poor cropping season may have to be considered depending on the
quantity and distribution of rainfall in July and August.
Seasonal forecasts for July to Sept rainfall; orange to browns, drier than average,
green shades wetter than average.
The season month by month
WEST AFRICA SEASONAL ANALYSIS - 2015
April 2015 rainfall as a percentage of the 20-year average (left). Brown shades for below-average rainfall; blue shades for above-average seasonal rainfall.
Early May 2015 vegetation index as a percentage of the 12-year average (right). Orange shades for below-average vegetation; green shades for above-average vegetation.
Hashed pattern indicates main agricultural areas.
April 2015
This month marks the very early stages of the growing season in West Africa. Normally by the end of the month, the growing season has extended
northwards up to northern Cote d’Ivoire across to central Nigeria and over into CAR.
This year, severe rainfall deficits in these regions delayed this progression of the growing season by 20-30 days which is reflected in lower than average
vegetation.
WEST AFRICA SEASONAL ANALYSIS - 2015
May 2015 rainfall as a percentage of the 20-year average (left). Brown shades for below-average rainfall; blue shades for above-average seasonal rainfall.
Late May 2015 vegetation index as a percentage of the 12-year average (right). Orange shades for below-average vegetation; green shades for above-average vegetation.
Hashed pattern indicates main agricultural areas.
May 2015
This month rainfall arrives in the Sahelian zone. The growing season usually starts in southern Mali, Burkina Faso, northern Nigeria and southern Chad. This year
rainfall deficits have spread across the regions, leading to a predominance of delayed starts to the season. Vegetation deficits have intensified which is a clear
indication of a poor start to the season and early crop development.
WEST AFRICA SEASONAL ANALYSIS - 2015
June2015 rainfall as a percentage of the 20-year average (left). Brown shades for below-average rainfall; blue shades for above-average seasonal rainfall .
Late June 2015 vegetation index as a percentage of the 12-year average (right). Orange shades for below-average vegetation; green shades for above-average vegetation.
Hashed pattern indicates main agricultural areas.
June 2015
This month rains arrive further into the Sahelian zone. This marks the start of the cropping season in south and central Senegal, and the main agricultural areas of
Mali, Niger and Chad.
Rainfall deficits continued to be the norm across most of West Africa, except for some areas in Mali. Elsewhere, there were either delays in the start of the season
or very poor conditions for the early crop development. Vegetation deficits are now very severe. Well distributed and plentiful July and August rainfall is now
essential to improve current prospects.
Data Sources:
Rainfall: CHIRPS, Climate Hazards Group, UCSB
Vegetation: MODIS NDVI, EOSDIS-NASA
Land Cover: FAO GLC-Share
Processing:
VAM software components, ArcGIS
For more information, please contact:
Rogerio Bonifacio
[email protected]
+39 06 6513 3917